Angular Motion and Definitions

Question 1

center of gravity

Answer 1

point around which all forces (weight) is balanced.

Not necessarily inside the body. when bending forward could be outside the body

Question 2

Moment of Inertia

Answer 2

the rotational equivalence to mass

I=mass* radius of rotation^2
I=mr62

units:kgm^2

Unlike mass, for which there is only one value, a new value exists for moment of inertia for each new axis that is chosen.

Question 3

Radius of Gyration

Answer 3

linear distance (m) between the axis of rotation to a point where body mass is concentrated

Question 4

Asymmetrical movements:

Answer 4

compensatory movement: COUNTER ROTATION kicking legs forward will cause body to move back

Initial movement:swinging arm at shoulder joint will cause whole body to rotate forward

Question 5

what is a moment

Answer 5

the turning effect that produces rotation= torque

Question 6

mechanical advantage

Answer 6

The mechanical advantage of a lever system is the ratio of the effort force
lever arm to the resisting-force lever arm.

A ratio of 1 indicates
no change in mechanical advantage,

less than 1 a decrease, and

greater than 1 an increase in mechanical advantage

second class levers have best mechanical advantage

Question 7

what is an impulse

Answer 7

change in momentum

part of Newtons 2nd law

Force x Time

Impulse= Ft

Question 8

angular momentum

Answer 8

The rotational equivalent of linear momentum

“amount of motion” a body posseses while in rotation

angular momentum= moment of inertia x angular velocity

angular momentum= Iw
angular momentum=mr^2(w)

Question 9

reference frame

Answer 9

An origin and a set of coordinate axes that serve as the basis for the
calculation of displacement and its derivatives.